Spectrophotometer multi-angle viewing device

ABSTRACT

A spectrophotometer multi-angle viewing device with a housing and holders for a test panel and reference standard. The holders allow rotation of a reference standard 360* in a vertical plane and rotation of a test panel 360* in a vertical plane and + OR 45* from the horizontal in a vertical plane perpendicular to the vertical plane in which the 360* rotation is possible.

United States Patent 1191 Armstrong, Jr. et al.

[54] SPECTROPIIOTOMETER MULTI- ANGLE VIEWING DEVICE [75] Inventors: William S. Armstrong, Jr., Phoenixville; Webster 11. Edwards, Springfield; Roy H. Vining, l-Iaverford, all of Pa.

[73] Assignee: E. I. du Pont de Nemours and Company, Wilmington, Del.

22 Filed: Jan. 12,1971 [21 Appl.No.: 105,843

' [52] US. Cl ..356/244, 356/212 [51] Int. Cl. ..G01n 21/16, G0ln 21/48 [58] Field of Search ..356/96, 195,205, 212, 244, V 356/246; 250/226 [56] References Cited UNITED STATES PATENTS 3,506,365 4/1970 Hunt at al ..356/244 [451 Jan. 23, 1973 Buc et al. ..356/244 Boostrom et al. ..356/96 FOREIGN PATENTS OR APPLICATIONS 392,300 3/1924 Germany ..356/244 Primary Examiner-Ronald L. Wibert Assistant Examiner-V. P. McGraw Attorney-John E. Griffiths [57] ABSTRACT A spectrophotometer multi-angle viewing device with a housing and holders for a test panel and reference standard. The holders allow rotation of a reference standard 360 in a vertical plane and rotation of a test panel 360 in a vertical plane and i 45 from the horizontal in a vertical plane perpendicular to the vertical plane in which the 360 rotation is possiblef 5 Claims, 5 Drawing Figures PATENTED JAN 23 I975 SHEET 1 0F 2 FIG. 2

INVENTORS WILLIAM S. ARMSTRONG, JR. WEBSTER H. EDWARDS ROY H. VINING A ORNEY PATENTEDJAN 23 ms SHEET 2 0F 2 FIG; 3

INVENTORS IILLIAI S. STRONG. JR. WEBSTER H. EDWARDS ROY H. VINIIG' I ZfiORNEY BACKGROUND OF THE INVENTION Spectrophotometers have commonly been used to measure reflectance values of various paint films which have been-coated over test panels. These values are fixed values which enable paint chemists to accurately produce color constants for various paint colors and thereby more accurately control paint production to a standard color by matching these values. For a paint, containing no light reflecting flakes or platelets, a single spectrophotometric reading at any angle of the panel relative to the direction of incident light will produce an accurate value.'Normal spectrophotometric panel holders possess means to hold a panel only at a fixed angle relative to the direction of incident light. However, as the paint industry recognized a need to become more sophisticated with respect to the aesthetic quality of their paint products, they began to utilize light reflecting flakes in their paints to obtain high glamour effects.

Paints containing light reflecting flakes such as aluminum mica and the like are characterized by a twotone or flip-flopeffect whereby the apparent color of the paint changes at different viewing angles. This effect is due to the orientation of the flakes in the paint film. Consequently values for a given test panel are different for various viewing angles and a single spectrophotometric reading at the usual angle normal to the plane of the panel no longer is sufficient. A series of readings at various angles must be taken in order to accurately'categorize a givencolor standard. Similarly, test panels coated with non-standard paints must be measured at the same angles used to characterize the standard in order to accurately compare the standard and nonstandard.

SUMMARY OF THE INVENTION 1 This invention relates to a device designed to be used in conjunction with a spectrophotometer for obtaining reflectance values in the form of spectrophotometric curves from panels coated with a paint.

An object of this invention is to provide a new and improved panel holding device which can be attached to a spectrophotometer. The apparatus is capable of being adjusted so as to provide a plurality of panel positions whereby any grazing angle can be obtained with respect to the direction of spectrophotometric light directed on the panel or a similarly held reference standard.

Another object of this invention is to provide a device of the character indicated whereby any of the plurality of angles at which the panel may be set can easily be duplicated for other samples.

BRIEF DESCRIPTION OF THE DRAWING In the drawing: FIG. 1 is a top view of the device partially in section with the top of the housing not shown.

7 FIG. 2 is a side view of the device in section.

FIG. 3 is a front view of the device. FIG. 4 shows the receiver of FIGS. 1 and 2 in greater detail and with the angle indicator removed.

- FIG. 5 is a front view of the positioning ring which can beturned to rotate the panel holder in a plane perpendicular to the direction of incident light from the spectrophotometer.

Referring to FIGS. 1, 2 and 3, there is shown a housing 5. The housing 5 is so structured that all external light is prevented from entering the housing. A door 9 is attached to the housing by hinge means 1 in order to provide easy access to the interior of the housing. A photocell or photomultiplier adapter 4 is fixedly attached to a sloped portion of the housing 5 as shown in FIG. 2 in order to allow light reflected from the test panel and reference standard to enter a photocell fastened to the photomultiplier adapter 4. An aperture as shown in FIG. 3 in the housing 5 is located below the photomultiplier adapter 4 to enable light emitted from the spectrophotometer to enter-the interior of the housing. Attachment of the device to the spectrophotometer is also made at this point.

Means for holding a reference standard 2, such as a barium sulfate disc, is attached to the housing 5 as shown in FIG. 1. This holding means consists of a shaft 6 which extends through the housing 5 into its interior and is rotatably attached to said housing 5. A reference disc can be fixedly attached to the end of the shaft 6 which can be cut in order that the reference standard is at a proper angle relative to the incident light, by any sort of fastening device so that the reference disc rotates with the shaft 6. Preferably the reference disc is fixed at an angle so that light reflected normal to the plane of the barium sulfate standard is reflected into the photocell. The shaft 6 extends to the outside of the housing where a turning handle 8 is fixedly attached to the shaft 6. The turning handle 8 can be used to impart rotation to the shaft 6. This rotation can be measured relative to a fixed circular positioning ring 18 incrementally marked in degrees which is attached to the housing 5 around the turning handle 8.

Also attached to said housing is means for holding a test panel 10 for which spectrophotometric curves are desired. This means 10 consists of a shaft 6' which extends through the housing 5 and is rotatably attached to said housing 5. This shaft 6' is situated in a horizontal plane with shaft 6 and is so positioned to hold a test panel at substantially the same distance from the spectrophotometer light source as is the reference disc. Fixedly attached to the end of the shaft 6' which extends inside the housing 5 is a fork means 3 to which a receiver 11 is pivotally attached by pivot pins 7,7 The use of the pivot pins 7,7 allows the receiver 11 to rotate through a plurality of vertical angles. The shaft 6 extends outside the housing 5 in similar manner to shaft 6. A turning handle 8' is fixedly attached to the end of shaft 6 and can be used to impart rotation to the shaft 6'. This rotation can also be measured relative to a fixed circular positioning ring 18' incrementally marked in degrees which is attached to the housing 5 concentrically around the turning handle 8'.

The receiver 11 is shown in FIGS. 1 and 2. It consists of a pressure plate 16 attached by hinge means 20 to a horseshoe shaped base plate 12 which forms an aperture whereby light can be focused from the spectrophotometer on the surface of a panel held in the receiver. The pressure plate 16 and the base plate 12 are of similar size and when in a position parallel to one another, they form a slot in which a test panel can be retained. Locking means 14 are provided to keep the panel held firmly in between the two plates. The horseshoe shaped base plate is attached fixedly to the pivot pins 7,7 at its outer edges. It should be noted that the structure defining the means for holding a test panel could be used in place of the aforementioned means for holding a reference standard with equal success.

As shown in FIG. 2, the degree of vertical rotation of the receiver 11 can be governed by an angle selecting means which consists of a notched circular ring 13 which fits concentrically around and is fixedly attached to the pivot pin 7 between the receiver 11 and the fork means. A lever 15 having a male head which operates by a compression spring 19 is pivotally attached to the interior edge of the fork means 3 and so positioned that it meshes with the notched circular ring 13 thereby securing a desired angular rotation of the receiver 11 in a vertical plane. A circular angle indicator ring 17 is fixedly attached to the pivot pin 7 at its exterior end parallel to the notched circular ring 13. The circular angle indicator ring 17 is incrementally marked in degrees in order that one can accurately reproduce a desired vertical angular setting.

In order to operate this apparatus, a test panel is placed in the receiver 11 and locked in place by the locking means 14. The receiver is set at a desired vertical rotation by releasing the pressure of the lever 15 from the notched circular ring 13, moving the receiver 11 as it pivots on the pivot pin 7,7 and releasing the lever 15 so that it meshes with the notched circular ring 13. The housing can be sealed by closing the door 9 to insure that no extraneous light enters the housing. Both the reference standard holder and the receiver can be adjusted for angular rotation in a plane perpendicular to the plane of vertical rotation previously established for the receiver 11, by rotating the turning handles 8 and 8 and consequently the shaft 6,6 to the same relative angular setting as determined by a reading of degrees in the fixed circular positioning rings 18,18.

At this time with the reference standard and the test panel similarly set relative to the angle of light emitted from the spectrophotometer, accurate characterization data can be obtained. Light is emitted from the spectrophotometer in an oscillating manner on to the panel and the standards which are situated on equal distance from the light source. This light is reflected into a photocell attached to the photomultiplier adapter 4 whereby it is converted into impulses which produce spectrophotometric curve reflectance data.

We claim:

1. A multi-angle viewing device comprising a housing, with a door hingedly attached thereto, means for holding and rotating a reference standard 360 in a vertical plane attached to said housing, wherein the means for holding and rotating a reference standard is a shaft rotatably attached to said housing and extending into the interior of said housing, said standard shaft cut at one end so as to allow a reference standard to be attached thereto, said standard shaft also having a turning handle fixedly attached thereto at a position outside said housing, means for holding and rotating a test panel 360 in a vertical plane and :45" from the horizontal in a vertical plane perpendicular to the verticaldplane in which 360 rotation is ossible attached to sai housing, each of said means emg so positioned that the reference standard and test panel are similarly situated with respect to incident light directed thereon through an aperture in said housing, wherein said means for holding and rotating a test panel is a receiver formed from a panel pressure plate hingedly attached to a panel base plate, said panel base plate pivotally attached to fork means to allow i45 vertical rotation from the horizontal, said forked means fixedly attached to a sample shaft which is rotatably attached to said housing and extends through said housing, and wherein a turning handle is fixedly attached to said sample shaft which extends outside said housing.

2. The multi-angle viewing device of claim 1 wherein circular positioning rings are concentrically mounted around the standard and sample shafts, respectively, said positioning rings fixedly attached to the housing, said circular positioning ring incrementally marked in degrees in order that precise rotational settings can be obtained.

3. The multi-angle viewing device of claim 2 wherein the panel base plate is horseshoe shaped so as to define an aperture whereby light can be focused on a panel contained in the receiver.

4. The multi-angle viewing device of claim 3 wherein the panel base plate is pivotally attached to the fork means by pivot pins, one of said pivot pins having fixedly attached thereto angle selecting means which consists of a notched circular ring attached concentrically around said pivot pin between the receiver and fork means and a spring operated lever pivotally attached to the interior of said fork means said lever being spring loaded and having a male head capable of mating with the notched circular ring thereby securing a desired angular rotation of the receiver.

5. The multi-angle viewing device of claim 4 wherein a circular angle indicator ring is attached to the pivot pin at its exterior end parallel to the notched circular ring, said circular angle indicator ring incrementally marked in degrees in order to accurately set vertical rotation of the receiver. 

1. A multi-angle viewing device comprising a housing, with a door hingedly attached thereto, means for holding and rotating a reference standard 360* in a vertical plane attached to said housing, wherein the means for holding and rotating a reference standard is a shaft rotatably attached to said housing and extending into the interior of said housing, said standard shaft cut at one end so as to allow a reference standard to be attached thereto, said standard shaft also having a turning handle fixedly attached thereto at a position outside said housing, means for holding and rotating a test panel 360* in a vertical plane and + OR - 45* from the horizontal in a vertical plane perpendicular to the vertical plane in which 360* rotation is possible attached to said housing, each of said means being so positioned that the reference standard and test panel are similarly situated with respect to incident light directed thereon through an aperture in said housing, wherein said means for holding and rotating a test panel is a receiver formed from a panel pressure plate hingedly attached to a panel base plate, said panel base plate pivotally attached to fork means to allow + OR - 45* vertical rotation from the horizontal, said forked means fixedly attached to a sample shaft which is rotatably attached to said housing and extends through said housing, and wherein a turning handle is fixedly attached to said sample shaft which extends outside said housing.
 2. The multi-angle viewing device of claim 1 wherein circular positioning rings are concentrically mounted around the standard and sample shafts, respectively, said positioning rings fixedly attached to tHe housing, said circular positioning ring incrementally marked in degrees in order that precise rotational settings can be obtained.
 3. The multi-angle viewing device of claim 2 wherein the panel base plate is horseshoe shaped so as to define an aperture whereby light can be focused on a panel contained in the receiver.
 4. The multi-angle viewing device of claim 3 wherein the panel base plate is pivotally attached to the fork means by pivot pins, one of said pivot pins having fixedly attached thereto angle selecting means which consists of a notched circular ring attached concentrically around said pivot pin between the receiver and fork means and a spring operated lever pivotally attached to the interior of said fork means said lever being spring loaded and having a male head capable of mating with the notched circular ring thereby securing a desired angular rotation of the receiver.
 5. The multi-angle viewing device of claim 4 wherein a circular angle indicator ring is attached to the pivot pin at its exterior end parallel to the notched circular ring, said circular angle indicator ring incrementally marked in degrees in order to accurately set vertical rotation of the receiver. 